Trend: Additive Manufacturing of Composites

Mat-Comp was present at the last two important events of the planet concerning composites: the JEC Show of Paris in March and the American CAMX in the fall of 2016. During these events, one can glimpse several trends related to raw materials, processes, equipment, tools, etc. Additive production is increasingly present there. It was also called “3D printing” or “rapid prototyping”. The mainstream media are much concerned about this type of manufacturing, promising an impending industrial revolution.

Ironically, the very principle of this “additive production” has been used for decades for the manufacture of composites. Indeed, instead of machining parts (subtractive manufacturing) we “add” the materials for the creation of shapes in successive layers to manufacture pieces of all kinds applied to different sectors.

What is changing today is the use of new robotic and digital technologies, as well as the democratization of these technologies.

It is understood that these techniques easily adapt to composites in different ways. Here are a few:

By using relatively traditional 3D printers, a thermoplastic filament reinforced with short fibres (even very short) can be introduced. The improved properties depend on the type of thermoplastic, the included fibre (glass or carbon) and the volume proportion of this reinforcement in the material. However, the performances are limited by the short fibre used.

The same techniques now make tooling (moulds, jigs, etc.) for the manufacture of composite parts directly (without “master” or model), in record time, in small and large dimensions. The promoters of these technologies even talk of a very significant reduction in tooling costs as several steps in the process are eliminated.

3D Printed mould (ref.: Stratasys)

For the past few years, new affordable 3D printers have been available to manufacture long fibre composites (glass, carbon or Kevlar reinforced Nylon). One could speak of revolution if the fibres were applied in the three axes, which is not the case. Never mind! Several research and development projects are under way to apply this technique. Robots equipped with heads specially designed to extrude long fibre reinforced thermoplastics or even long fibre reinforced thermosets. The beauty is that this technology makes it possible to apply the material in all directions. There, we talk about real composites produced additively.